System for electronically controlling LED-array image printer

Abstract

A system for controlling an image printer including a scanning LED array is provided. An image printer control unit receives page profile and raster image data and converts the raster image data into parallel image data corresponding to the configuration of the LED array. Advantageously, the image printer control unit optimizes the number of lines of information printed during a scan to reduce splitting of characters between scans and coordinates printhead and photosensitive medium position. Interlaced scanning for high resolution is also provided. In an alternative embodiment image data is received in parallel vertical slices and bands for which no exposure is to be made are skipped.

What is claimed is: 
     
       1. A method of controlling an image printer including an LED array printhead that is scanned perpendicular to the direction of travel of the photosensitive medium being exposed, comprising the steps of: providing raster image data to an image printer control unit;   storing at least a portion of said raster image data in memory within said image printer control unit;   designating as exposure bands each set of exposure data within said stored raster image data corresponding to one complete scanning exposure of the LED array;   identifying from said exposure data for each exposure band any scan line for which no information is to be printed;   terminating the exposure scan of the LED array on a scan termination line where no information is to be printed; and   commencing the next exposure scan on a line subsequent to said exposure scan termination line.   
     
     
       2. The method according to claim 1 further comprising the steps of: directing the printhead to skip lines for which no information is to be printed to commence scanning exposure on the next line for which an exposure is to occur.   
     
     
       3. The method according to claim 2 further comprising the step of: directing the printhead to terminate a first exposure scan and advance to the next scan where not further exposure is to be made during the remaining portion of the first scan.   
     
     
       4. The method according to claim 2 wherein motor controlling means drives the scanning printhead and advances the photosensitive medium. 
     
     
       5. A method of controlling an image printer including an LED array printhead scanned perpendicular to the direction of travel of the photosensitive medium being exposed, comprising the steps of: providing raster image data to an image printer control unit;   storing at least a portion of said raster image data in memory within said image printer control unit;   designating as exposure bands each set of exposure data within said stored raster image data corresponding to one complete scanning exposure of the LED array;   identifying each scan line within each said band of exposure data for which no scanning exposure is to be made;   causing said LED array printhead to skip exposure bands for which no exposure is to be made.